<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <div id="app">
        <div>
            {{ msg | formatMsg }}
        </div>
    </div>

    <script src="./vue.js"></script>
    <script>
        new Vue({
            el: '#app',
            data: {
                msg: '马杀鸡',
                gsm: '鸡杀马'
            },
            filters: {

                formatMsg (val) {

                    // 过滤器里的this是window
                    // 所以无法访问当前vue实例里的数据
                    // 有些人也把这个称之为过滤器里没有this
                    console.log(this)
                    return val + this.gsm
                }
            }
        })
    </script>
</body>
</html>